The present invention relates to a piston and cylinder configuration for positive expulsion purposes. Specifically, in the field of liquid plants or the like, it has been the general practice to employ pistons with dynamic seals (i.e. O-rings or wiper seals), or rolling metal bladders or collapsing metal bladders to provide positive expulsion of propellants (i.e. fuel and oxidizer). However, such prior art devices have been unsatisfactory for various reasons. For example, rolling metal bladders having a centrally located piston guide eliminate the need for dynamic seals but present problems of piston-head cocking and rapid pressurization forces. As well, rolling metal bladders are utilized only with low length to diameter ratio application. Collapsing metal bladders present problems of metal folding and tearing, of requiring internal pressurization during storage to prevent bladder movement and fatigue, and of causing greater movement of the propulsion system center of gravity during operation than pistons or rolling metal bladders. For high Length to Diameter ratios, 3.0 to 1.0 and greater, positive expulsion piston tankage represents the most efficient solution to the aforementioned problems.
Numerous fluid storage and expulsion systems are disclosed in the art.
For example, U.S. Pat. No. 4,723,736 to Rider relates to a rocket staging system for missiles and the like wherein a carriage borne rocket engine assembly is sequentially employed within separate, generally aligned oxidizer stages which are generally coaxially disposed about the central rocket engine. In this way, a central fuel tank is surrounded by several, separate, cooperating, generally ring-shaped oxidizer tanks coaxially disposed about the rocket periphery.
U.S. Pat. No. 3,668,868 to Krzycki is directed to a prepackaged liquid rocket power plant feed system having mechanically linked pistons attached to longitudinally involuted rolling metal bladders. Specifically, each propellant tank contains a rolling metal bladder positive expulsion device in which the propellant is hermetically sealed and stored.
U.S. Pat. No. 3,216,621 to Versaw et al. relates to a storage and expulsion system wherein the maximum available storage space is utilized irrespective of tank-shaped irregularities.
U.S. Pat. No. 2,874,539 to Fox relates to a continuous combustion power plant in which the fuel and oxidizer are introduced so that gentle mixing occurs.